Carbocyclic analogues of nucleosides are described in European Patent Application Publication No. 345,076 published Dec. 6, 1989 as being useful as pharmaceuticals in the treatment of viruses, especially Herpetoviridae. A particular compound described is (1'S, 3'S, 4'S)-2-amino-1,9-dihydro-9-[3,4-dihydroxy-3-hydroxymethyl-1-cyclopentyl]-6 H-purin-6-one of the following formula (I): ##STR2##
European Patent Application Publication No. 349,242 published Jan. 3, 1990 assigned to the Wellcome Foundation teaches 6-substituted purine carbocyclic nucleosides and Example 45 provides a synthesis of (.+-.)-9-[3-(hydroxymethyl)-3-cyclopenten-1-yl]guanine (racemic compound of formula V).